Boston Marathon explosions: 3 dead, more than 100 hurt

Reuters

Two bombs ripped through the crowd at the finish line of the Boston Marathon on Monday, killing three people, maiming others and injuring more than 100 in what a White House official said would be treated as an "act of terror."

It was the worst bombing on U.S. soil since security was tightened after the attacks of Sept. 11, 2001, and President Barack Obama promised to hunt down whoever was responsible for the attack on a day when tens of thousands of spectators packed the streets to watch the world-famous race.

No one has been arrested and the White House official said it would have to be determined whether the attack came from a foreign or domestic source.

Investigators found what could be five additional, undetonated explosive devices around the Boston area, the Wall Street Journal reported, citing two unnamed people briefed on the investigation. The evidence had yet to be fully analyzed, the Journal said.

The blasts a few seconds apart knocked some runners off their feet and shattered what had been a resplendent spring day with the state of Massachusetts celebrating Patriots' Day, which commemorates the U.S. war of independence on the third Monday in April.

April 15 is also the deadline for U.S. taxpayers to file their annual income tax returns.

Many runners were heading for the finish when a fireball and smoke rose from behind cheering spectators and a row of flags representing the countries of participants, video from the scene showed.

The cheers turned to screams and panic.

"I saw people who looked like they had their legs blown off. There was a lot of blood over their legs. Then people were being pushed in wheelchairs," said Joe Anderson, 33, a fisherman from Pembroke, Massachusetts, who had just run the race holding a large U.S. flag.

The two explosions at 2:50 p.m. (EST) were about 50 to 100 yards (metres) apart as runners crossed the finish line with a timer showing 4 hours and 9 minutes, some 9 minutes faster than the average finish time, as reported by Runner's World magazine.

Spectators typically line the 26.2 mile race course, with the heaviest crowds near the finish line.

Mike Mitchell of Vancouver, Canada, a runner who had finished the race, said he was looking back at the finish line and saw a "massive explosion."

Smoke rose 50 feet in the air, Mitchell said. People began running and screaming after hearing the noise, Mitchell said.

"Everybody freaked out," Mitchell said.

The annual Boston Marathon, held since 1897, attracts an estimated half-million spectators and some 20,000 participants every year.